Spark-plug.



D. W. SHANNON & T. N. HARRIS.

SPARK PLUG.

APPLlc/Tmu man 553.6. ma.

1,293,218, v Patented Feb. 4,1919.

III

ATTORNEY n srA'rEs PATENT ocu.-

UNCAN' W. SHANNGN ANB TIEIADDEUS N. EABJRS, 03? KEY WEST, FLORIDA.

struction and operation which may be readily applied to an internalcombustion engine of standard construction. A further object is toprovide a plug the various parts Lof which maybe quickly and easilydisassembled for cleaning or repairing. `further object is to provide aspark plug provided with means for securing the terminal carryingelements in proper position and for also closing theicasing whichcarries the plug when the plug is-removed'thus permitting the plugto beremoved without stopping the engine. 'Further objects will appear fromthe detailed description.

In the drawings: Figure 1 is a longitudinal section through a plugconstructed in accordance with our invention.

. Fig. 2 isa top plan view vof theplug.

Fig, 3 is a longitudinal section through the plug showing the terminalcarrying members in partial withdrawn position.

-The body orcasing 1 of the plug is of usual construction being providedintermediate its ends with an integral nut 2 and having the taperedthreaded. neck 3 which is adapted to be threaded into the usual bore 4provided in the cylinder head 5. rlhe casing l receives acylindrical'metallic sleeve G threaded therein. This sleeve is providedat its outer end with a hexagonal head 7 which facilitates threading ofthe sleeve into and out of the casing. Head 'i' is provided with acentral cylindrical recess which receives the threaded neck 8 of asecuring nut 9. A tube 10 of porcelain or other suitable insulatingmaterial is mounted yin tube 6.

and is provided, at its inner end, with a tapered portion 11. This tubeis provided with a terminal member 12 in the form of a metallic rodwhich extends the full length of the tube, the inner end of this rodbeing spaced over the arcuate terminal member 13 Specification ofLetters atent.

SPARK-PLUG.

Patented Feb. 4, 1919.`

Application led February 6, 1918. Serial No. 215,653.

carried by the tube 6 at the innerA end thereof. The tube 6 is providedat its inner-' end with an inner annular shoulder 14 which; engages theshoulder at the' inner end Ior tube, 10 formed by the reduced portionl1. This' shoulder acts to positively limit thev inwardmovement of thetube. The outer portion l1a of tube 10 is slightly tapered, and thesecuring nut 9 is provided with aeorresponding axial bore. By threadingnut 9 into head 7 the insulating tube 10 is forced inwardly and securedin proper position so as to. have the terminal members disposed in.proper spaced relation. A metallic disk 15 is secured on the outer endof tube l0 and carries Y ner end of this screw engages into an annulargroove 20 fornied'in the outer face of sleeve 6. In this manner screw 9eiectually prevents rotation of the-sleeve thus securi the contactpoints in proper relation to eald other.

ln use'this spark plug will operate in the well known manner, theterminal rod 12 being connected to one side of the battery through theusual induction coil, and the engine being grounded to the other side ofthe battery. if the plug needs to be cleaned or repaired while theengine is in opera-tion, this may be effected without stopping theengine. By turning' the screw 19 out of engagement with the tube 6, thetube and the elements carried thereby may be readily removed from thebody or casing 1. When the sleeve has been turned outwardly a sufficientdistance to insure that the inner terminal member 13 is beyond the screw19, screw 19 is then turned in so as to extend completely across thebore of body 1 thus efectually closing the same, it being understood, ofcourse, that the diameter oi.l the screw is slightly greater than theinterior diameter of casing 1. After the screw has thus been turned inso as to close the casing, the sleeve 6 and the parts carried therebymay be completely removed thus permitting the plug to be quickly andeasily cleaned or repaired.

During the repairing or cleaning of the y :.plug, it is not necessaryIto stop the engine as the casing 1 is closed, as above noted. 'When theplug has'been repaired it may be threaded into the casing l'a shortdista-nce, after which the screw 19 is turned out so as to clear thesleeve,- the tube then being threaded inward into its innermostposition.

'26 ed in said casing, means for releasably securing said tube in thecasing, said securing means being adapted to close the casing when thetube' is removed therefrom.

2. In spark plugs, a casing having a longitudinal threaded bore and atransverse threaded bore intersecting the same, a sleeve Athreaded intosaid longitudinal bore and containing any insulating element, the sleeveand element carrying the terminals, and a screw threaded into vsaidtransverse bore .against the sleeve, the screw being of a size to beprojected across the longitudinal bore when the sleeve is withdrawn andclose said bore at that time.

3. In a spark plug, the combination with a casing having a longitudinalthreaded bore and a diametric threaded bore intersecting the same, saidbores being of approximately the same size; of a sleeve threaded intosaid longitudinal bore and having an external annular groove adapted toregister .with said diametric bore when the sleeve 1s 1n properposition, an insulating element carriedwithin the sleeve, terminalscarried by theA sleeve and element, and a screw threaded into saiddiametric bore and engaging said groove when the sleeve is in place oradapted to be projected across its longitudinal. bore to close the samewhen the sleeve is withdrawn. v

4. In spark plugs, a casing having a longitudinal bore, a tube threadedthrough said casing, the casing being also provided with a diametricalbore, and a screw threaded into said diametrical bore for engagementwith the tubeso as to normally prevent ro1 tation thereof, said screwbeing adapted to extend across the interior ofsaid casing so as tocompletely close'thesame when the tube is removed.l

v5. In spark plugs, a casing, a tube mounted in said easin and providedat its inner end with a terminal member, means for. releasably securingsaid tube in the casing, and a terminal member carried b andelectrically insulated there om, said terminal member being spaced fromthe first mentioned terminal member, and said securing means beingadapted to close the casing when the tube is removed therefrom.

In testimony whereof We aiiix our signatures in presence of twoWitnesses.

DUNCAN IV. SHANNON. THADDEUS N. HARRIS. Witnesses:

H. J. CANNIS, SYDNEY STUART.

Copies of this patent niay be obtained for ve cents each, by addressingthe Commissioner of Patents,

Washington, D. C.

the tubei

